Control system for engine generator units



Aug.-31, 1948. D. R. STAPLES ETAL CONTROL SYSTEM FOR ENGINE GENERATORUNIT v Filed Dec. 22, 1945 Patented Aug. 31, 1948 CONTROL SYSTEM'FORENGINEVv GENERATOR UNITS Dana' It. Staples; Ridley" Park, and John' J.Stamm, Chester' Heights', Par., assgnors' to The Baldwin' LocomotiveWorks,V acorp'oraton of Pennsylvania ApplicationDecember 22, 19215',Serial No. 637;()66' S'lCIaiins.' 1

` 'Ihis'invention'relates `tomotor'control systems ofthe type'in whicha' generator' supplies power t'o'motors'an'dha's' ior'an object'theprovision of 'means for" graduallyY and' smoothly increasing' ordecreasing 'thep'owersupplied to the' motors un'- 'd'er the control; ofl'a manually 'operable' master controller.'

In' locomotives" provided with aprime' mover such' as'an internalcombustion engine orDiesel engine; together'with a generator driventhereby for 'supply of'p'ower to' traction motors, it is' desirableinmany'cases'to have the applicationv of power' under' tlie'control'of anengineman and' to minimize` change'of power foreach" step of" theengineman's throttle.

'In carryin'g'out the present invention in one form thereof; theexcitation' of the main'power generator' ofthe' locomotive is controlledin accordance' with' the' movement of the `enginemaris throttle. Therehas been eliminated step byistep changes in the excitation. For 'eachmovement ofL the throttlethere is a corresponding change inthe'excitation'of 'tliemaingeneraton Moreover; after full excitation hasbeen-produced on the main generator; the throttle'then'increa'sesthepower developed by'the primemover in accordance with'the position ofthe throttle.

f For "amore complete understanding of the invention and i or furtherobjects and 'advantages thereof, 'reference should be had to the followeing descriptiontaken in conjunction-with the ac# companying drawing'which diagrammatically illustrates atypical 'embodiment of'v theinvention.

Referring to'the drawing, the' invention in'one form has-beenfshownasapplied to 'a locomotive of the typedn'wliich-a suitable-prime mover,as a Diesel engine II), is' utilizedto drive a* main powergenerator I Ihaving av separately 'excited meldt-'winding'V I3, Though' theexcitation ofthe eldwinding `I3 may be directly! controlled by means ofvariable resistors, it is shown'as'under the control of an exciterI4also'drivenby'the Diesel en'g-ine-A I0. A resistor IBfm'ay'be`included in :the circutvincluding the main field winding I3 ofYthe'generator II. The'exciter I`4`is provided with'a differential fieldwinding"l6` connected'in series with the generator II. The exciter'isValso providedwvith'a' separately excitedeld' winding II`.AThe-.generator'is arranged to supply 'current toone-or'more motorsvonly one of which; the motor' |82 is shown. It is provided with a seriesfield 'winding' I9, the 'polarity-of vwhich is under the `control vof areversing switch 20 `operated` by pneumatic means'2I. The supply vofpower to the motor' l'lisunder 'the control of a contactor'22',

2v, The'prime 'mover' I l)= is'vprovided' with '-a'- governor 23 :forcontrolling'the power output thereof.

The excitation" of excitery I4"isl controlledby means 'of avariable'resistor, preferably a' carb'on pile'24} the resistanceofwhi'ch may be gradually decreasedby'rotati'on of "thelever' 25 inacountei-:clockwise direction around its pivot 2S: Nor'i mally,the'lever 25'is 'biased against' a' stop Z-Iiby means of' a' springr23.' The lever' 25' is actuated through'a'link 29, a crank arrn30,lalinlr 3I-and a'lever'32 operable by "a 'pneumatic' device'33.Th'e'devic'e' 33" consists of 'a flexible diaphragm 34 which upon'application of air'pressure'- thereto asbywa'y 'of pipe"35"moves aro'd36 downwardly against the bias'of 'a' springv 31;' The rodis 'pivotedat'38 to the lever 32"wl'ii'chis also'pivote'dat 39. Thus 'asairpressure is appliedto" the device" 33 the resistan'ceof the 'carbonpile'`2 @decreases and as'thel'airpr'essure' is 'relieved'the'springsV 3T iand Z'Spro'duce" anvincr'ease in theV resistance of-'the carbon' pile'2'4. n

In theoper'ation' of the "invention, the locomotivefopera'tor or`engineman 'rst moves afleverl'll to the'rig'ht ortheleft'partiallytocomplete-an energizing 'circuit"'through'th'e forwardor reverse contacts` 4l' and 42. He thereupon movesl the main'controller handle o rthrottle 43 to itsrst p'osition'to complete "acircuit from a'supplyfline through contacts andby Way of Vconductorsli''an'd'll to 'a conductor '48"connectedito one'iof the terminals ofeach 'of theforward and -reverse contactslll and'li. Thus', uponmovementof"the handlefili to `close'the contactsll, an energizingcircuit is completed'for' the operatng'coil`5'lof a'valve 491 This"circuit may be tracedfrom the contacts 4I by'way of conductor 50,' theoperating coil' 5I andto the'other supply line 5'2'2 Thereupon the valve'49 will vbe 'opened to' admit" air into the pneumatic actuator'l 2l-to' move the'pistonl to the illustratedV position' for' connection 'ofthe series-winding 'I 9 for' forward rotation Lof the motor'` l8.The'c'oil 51| "also closes contacts 5'5 t0 complete'an energizingcircuitffor the operating -coil `SGSO'the contacter 22.' This'circuit is`uthe samer as the Zonepreviouslytrace'dup'to the pointfof'coninectiontothe contacts-" by conductor 50. The circuit vthen 'extends byway "of fconductors i511 e and Esto' the operating coil`56 andthence to the'other supply line 52; The contacter Z'Zthereupon closes toconnect thegenerator II` to the motorv VI8-'and alsoto'close contacts illtocomplete an energizing 'circuit forthe-'opera'ting'coil 6I of/acontactor E22 This'contactor thereupon closes to complete the energizingcircuit' for' theI field" winding'v I1=-. v'lfiiis circuitnia'y beltraced" by' way'of the supply line 44, contacts 45, conductors 46 and41, contacts 63, carbon pile 24, conductors 64 and by the iield windingIl to the other supply line 52.

It will be remembered that the carbon pile 24 is fully expanded; thatis, no pressure has been applied thereto and its electrical resistanceis a maximum. In consequence, there is little flow of current throughthe eld winding l1 upon closure of the contactor 62.

The foregoing operations take place rapidly. It is unnecessary for theengineman to hold the throttle 43 in the rst position. After operationof the lever 45) the main throttle 43 is moved to its rst position forclosure of'the contacts 45 and progressively in the same direction toincrease the power supply to the motor i8. This is accomplished by apneumatic controller 56 directly operable by the throttle 43 by means ofa shaft 61 which drives a gear 68 in mesh with a gear 69 of thecontroller 65. The operation of the controller 66 is well understood bythose skilled in the art and it serves to deliver to the pipes 35 and'Hl air at a pressure dependent upon the position of the throttle 43.The controller 65 is supplied with air at suitable pressure by way ofsupply pipe l I. Briefiy, the operation of the controller 66 is asfollows. The gear 69 rotates a cam yoke 'l2 which is moved downwardly bythe cam carried by the housing 14. The downward movement of the yoke 12moves the exhaust valve seat 'l5 downwardly into engagement with theexhaust valve 76. Further movement of the yoke l2 unseats an inlet valve'll permitting air to ow from the supply line 'll through the chamber'EB upwardly through vthe inlet valve 'll and into a cavity 'i9 to whichis connected the pipes lil and 35. Thus, the air pressure in these pipesis immediately increased. However, it will be observed vthe increasedair pressure is applied through an opening 80 to the upper side ofdiaphragm 8l which is thereby moved downwardly to reseat theinlet valveTl. If the throttle 43 is moved a greater distance, the yoke 12 will bemoved downwardly again to open theinlet valve 'll and vfurther toincrease the pressure delivered to the supply pipes 35and lll. Thesprings 82, 33 and 34 are selected in terms of the pressure to bemaintained in the supply pipes 35 and lil. It is to be understood thatreverse movement of the throttle 43 will permit the springs to lift theyoke 'l2 thus lifting the-exhaust valve seat l5 to unseat the valve 16releasing air from the supply lines and 7B, from the -cavity or chamberi9 and from above the diaphragm 8| by way of the opening 8G. However, asthe air pressure decreases above the diaphragm EH the spring 82 raisesthe exhaust valve 76 to its closed position. Thus the pressure in thelines 35 and 'ill is controlled with the extent of movement of thethrottle 43.

The rising pressure in the line 35 is applied to the pneumatic actuator33. Consequently, its lever 32 is moved in accordance with the movementof the main throttle 43; that is, the movements are related until thelever 32 operates the lever 25 fully to compress the carbon pileresistor 24 to reduce its resistance to a minimum. The result of theforegoing is that the excitation current for the eld winding Il isincreased at a rate vcorresponding with the movement of the maincontroller 43 and the rate of rise of the air pressure supplied to theactuator 33. Accordingly, the excitation of the main eld winding E3 ofthe generator H is increased and power supplied to the motor I8 islikewise increased.

It is a feature of the present invention that the governor or throttle23 of the prime mover l0 is also under the control of the maincontroller handle 43. This is accomplished by providing a pneumaticactuator 90 having a spring 3l which is stronger than the spring 3l ofthe actuator 33. The arrangement is such that the piston 92 of theactuator Si) does not begin to move until the air pressure has moved thelever 32 fully to compress the carbon pile resistor 24. Thereafter,

additional movement of the main controller handle v43 further increasesthe pressure in the pipe 'Hl and thus moves the piston 92 and throughlinks S3 and 94 moves the governor or throttle 23 of the primer moveril) in a direction to increase the power delivered to the generator ll.

It will now be understood that the system may be modified withoutdeparting from the invention; for example, the spring 9i may be selectedorset for operation of the actuator el before the carbon pile resistor24 has been fully compressed. However, in accordance with the inventionthe locomotive 'operator not only has control over the applicationofpower to the motors during starting but he is also assured of smoothstarting due to the increase in excitation of the main generator Hpriory to substantial movement of the throttle Z3 to increase the powerdelivered to the generator and the motors. The increasing flow of poweris relatively important in starting a locomotive because the applicationof power at a high rate frequently results in wheel slippage. Inaccordance with the invention, a locomotive and train increases itsspeed at a smooth even rate uninterrupted by jerks or jolts which arecommonly associated with the starting of a train.

When the controller handle 43 is rotated toward its initial position itwill be understood the foregoing operations will be carried out inreverse order. When the initial position is reached, the contacts 45will be opened to de-energize the operating coils 5|, 56 and 6l.

For reverse movement of the train or locomotive, the reversing lever 43,with the motor l 8 de-energized, is moved to open the previously closedcontacts4l and to close the contacts 42. The circuit to the operatingcoil 5| is thereby openedfor operation of the valve 49 to its closedposition. An energizing circuit is partially completed for the operatingcoil 96 of a valve 91 which admits air to the opposite side of piston 54for movement of the reversing switch to its other position.V Contacts 98serve to complete the circuit to the operatingv coil 5t of the contactor22. Upon movement of the controller handle 43 to its rst position theoperations first described are again carried out for acceleration of themotor I8, thistime in thc-:reverse direction.

While a preferred embodiment of the invention has been described, it isto be understood modications may be made within the scope of theappended claims.

What is claimed is:

l. The combination with an engine, a generator driven thereby and atleast one motor supplied by said generator, of means for controlling theexcitation of said generator comprising a variable resistor, a pneumaticactuator biased to one position and operable from that position underpneumatic pressure for gradually changing-the resistance of saidresistor between minimum and maximum values, a pressure regulator forcontrolling the pressure to said actuator, control means operablethrough a plurality of cation of diierent pressures to said actuator,and

pneumatic means operable as said resistor develops its minimumresistance for increasing the power delivered by said engine to saidgenerator.

2. The combination with an engine, a generator driven thereby and atleast one driving motor supplied to said generator, of means forcontrolling the excitation of said generator comprising an adjustableresistor, a pneumatic actuator for said adjustable resistor biased toone position and operable through a range of movement to change theresistance of said resistor, a pressure regulator having a controlmember the position oi which determines the pressure applied to saidactuator, control means connected to said control member and operablethrough a plurality of positions smoothly to Vary said air pressure froma minimum to a maximum pressure smoothly to change the resistance ofsaid resistor from maximum to minimum values, for a change in airpressure from said minimum value to one below said maximum value,load-controlling means for said engine, a second pneumatic actuator forsaid load-controlling means and operable at said minimum pressure tolimit the output of said engine and operable after said resistordevelops its minimum resistance for increasing to its full load valuethe power delivered by said engine to said generator.

3. The combination with an engine, a generator driven thereby and atleast one motor supplied by said generator, of means for controlling theexcitation of said generator comprising a carbon pile resistor, apneumatic actuator for gradually changing the resistance of saidresistor between minimum and maximum values, a pressure regulator forcontrolling the pressure to said actuator, control means operablethrough a plurality of positions for adjusting said regulator forapplication of different pressures to said actuator, and pneumatic meansoperable as said resistor develops its minimum resistance for increasingthe power delivered by said engine to said generator.

4. The combination with an engine, a generator driven thereby and atleast one motor supplied by said generator, of a field Winding for saidgenerator, an exciter for said field Winding, a field Winding for saidexciter, a carbon pile resistor connected in circuit with said excitereld winding for controlling the excitation thereof, a pneumatic actuatoroperable upon application of pressure to reduce the resistance of saidresistor to a minimum value, a regulator for varylng the pressureapplied to said actuator, a controller operable through a plurality ofpositions for adjusting said regulator gradually and uniformly to changethe pressure applied to said actuator for smoothly and graduallychanging the excitation of said exciter, a throttle for said primemover, and a pneumatic actuator therefor connected to said regulator forcontrolling the setting of said throttle, said second named actuatorbeing effective only after said first-named actuator has reduced theresistance of said carbon pile resistor to substantially its minimumvalue.

5. The combination with an engine, a generator driven thereby and atleast one motor supplied by said generator, of means for controlling theexcitation of said generator comprising a resistor of the compressibletype, a pneumatic actuator therefor, a pressure regulator having acontrol member the position of which determines the pressure applied tosaid actuator, control means connected to said control member andoperable through a plurality of positions smoothly to vary said airpressure from a minimum to a maximum pressure smoothly to change theresistance of said resistor from maximum to minimum values, for a changein air pressure from said minimum value to one below said maximum value,loadcontrolling means for said engine, a second pneumatic actuator forsaid load-controlling means and operable at said minimum pressure tolimit the output of said engine and operable after said resistordevelops its minimum resistance for increasing to its full load valuethe power delivered by said engine to said generator.

DANA R. STAPLES. JOHN J. STAMM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 776,223 Deutsch Nov. 29, 1904790,819 Dorman May 23, 1905 1,216,237 Lemp Feb. 13, 1917 1,271,788 Snee,Jr July 9, 1918 1,745,130 Turner Jan. 28, 1930 1,821,827 BrandensteinSept. 1, 1931 1,891,936 Lemp Dec. 27, 1932 2,050,068 Schaer Aug. 4, 19362,060,900 Simmen Nov. 17, 1936 2,131,527 Sousedik Sept. 27, 19382,180,138 Brunner Nov. 14, 1939 2,231,521 Curry Feb. 11, 1941 2,290,867Curry July 28, 1942 2,424,121 Schlapfer July 15, 1947 Certicate ofCorrection Patent No. 2,448,284. August 31, 194s. DANA R. STAPLES ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Column 5,line 6, claim 2, for the words to said read by said; and that the saidLett-ers Patent should be read with this xiireetion therein that thesame may conform to the record of the oase in the Patent Signed andsealed this 16th day of November, A. D. 1948.

THOMAS F. MURPHY,

Assistant Uommz'ss'ioner of Patents.

Certificate of Correction r Patent No. 2,448,284. August 31, 1948. DANAR. STAPLES ET AL.

r appears in the printed specification of the above l It is herebycertified that erro numbered patent requiring correction as follows:Column 5, line 6, claim 2, for the Wi Words to said read by said andthat the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOfiiee.

Signed and sealed this 16th day of November, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Potente.

